Electrochemical performances of nickel‐rich single‐crystal LiNi0.83Co0.12Mn0.05O2 cathode material synthesized by tuning Li+/Ni2+ mixing

Single-crystal nickel-rich materials are promising alternatives to polycrystalline cathodes owing to their excellent structure stability and cycle performance, while the kind of cathode material usually appears high cation mixing, which may have a negative effect on its electrochemical performances. The study presents the structure evolution of single-crystal LiNi0.83Co0.12Mn0.05O2 in the temperature-composition space using temperature-resolved in-situ XRD and its cation mixing is tuned to improve electrochemical performances. The as-synthesized single-crystal sample shows high initial discharge specific capacity (195.5 mAh g−1 at 1 C), and excellent capacity retention (80.1% after 400 cycles at 1 C), taking account of lower structure disorder (Ni2+ occupying Li sites is 1.56%) and integrated grains with an average of 2~3 μm. In addition, the single-crystal material also displays a superior rate capability of 159.1 mAh g−1 at the rate of 5C. This excellent performance is attributed to the rapid Li+ transportation within the crystal structure with fewer Ni2+ cations in Li layer as well as intactly single grains. In sum, the regulation of Li+/Ni2+ mixing provides a feasible strategy for boosting single-crystal nickel-rich cathode material.